linux.git/kernel/acct.c, branch v6.12.80

acct: block access to kernel internal filesystems

2025-02-27T12:30:23+00:00

commit 890ed45bde808c422c3c27d3285fc45affa0f930 upstream.

There's no point in allowing anything kernel internal nor procfs or
sysfs.

Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com
Link: https://lore.kernel.org/r/20250211-work-acct-v1-2-1c16aecab8b3@kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Amir Goldstein 
Reported-by: Zicheng Qu 
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner 
Signed-off-by: Greg Kroah-Hartman

acct: perform last write from workqueue

2025-02-27T12:30:23+00:00

commit 56d5f3eba3f5de0efdd556de4ef381e109b973a9 upstream.

In [1] it was reported that the acct(2) system call can be used to
trigger NULL deref in cases where it is set to write to a file that
triggers an internal lookup. This can e.g., happen when pointing acc(2)
to /sys/power/resume. At the point the where the write to this file
happens the calling task has already exited and called exit_fs(). A
lookup will thus trigger a NULL-deref when accessing current->fs.

Reorganize the code so that the the final write happens from the
workqueue but with the caller's credentials. This preserves the
(strange) permission model and has almost no regression risk.

This api should stop to exist though.

Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com [1]
Link: https://lore.kernel.org/r/20250211-work-acct-v1-1-1c16aecab8b3@kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: Zicheng Qu 
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner 
Signed-off-by: Greg Kroah-Hartman

kernel misc: Remove the now superfluous sentinel elements from ctl_table array

2024-04-24T07:43:53+00:00

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove the sentinel from ctl_table arrays. Reduce by one the values used
to compare the size of the adjusted arrays.

Signed-off-by: Joel Granados

fs: rename __mnt_{want,drop}_write*() helpers

2023-09-11T13:05:50+00:00

Before exporting these helpers to modules, make their names more
meaningful.

The names mnt_{get,put)_write_access*() were chosen, because they rhyme
with the inode {get,put)_write_access() helpers, which have a very close
meaning for the inode object.

Suggested-by: Christian Brauner 
Link: https://lore.kernel.org/r/20230817-anfechtbar-ruhelosigkeit-8c6cca8443fc@brauner/
Signed-off-by: Amir Goldstein 
Message-Id: <20230908132900.2983519-2-amir73il@gmail.com>
Signed-off-by: Christian Brauner

Merge tag 'audit-pr-20230829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

2023-08-30T15:17:35+00:00

Pull audit updates from Paul Moore:
 "Six audit patches, the highlights are:

   - Add an explicit cond_resched() call when generating PATH records

     Certain tracefs/debugfs operations can generate a *lot* of audit
     PATH entries and if one has an aggressive system configuration (not
     the default) this can cause a soft lockup in the audit code as it
     works to process all of these new entries.

     This is in sharp contrast to the common case where only one or two
     PATH entries are logged. In order to fix this corner case without
     excessively impacting the common case we're adding a single
     cond_rescued() call between two of the most intensive loops in the
     __audit_inode_child() function.

   - Various minor cleanups

     We removed a conditional header file as the included header already
     had the necessary logic in place, fixed a dummy function's return
     value, and the usual collection of checkpatch.pl noise (whitespace,
     brace, and trailing statement tweaks)"

* tag 'audit-pr-20230829' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: move trailing statements to next line
  audit: cleanup function braces and assignment-in-if-condition
  audit: add space before parenthesis and around '=', "==", and '<'
  audit: fix possible soft lockup in __audit_inode_child()
  audit: correct audit_filter_inodes() definition
  audit: include security.h unconditionally

acct: replace all non-returning strlcpy with strscpy

2023-08-18T17:18:51+00:00

strlcpy() reads the entire source buffer first.  This read may exceed the
destination size limit.  This is both inefficient and can lead to linear
read overflows if a source string is not NUL-terminated [1].  In an effort
to remove strlcpy() completely [2], replace strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Link: https://lkml.kernel.org/r/20230710011748.3538624-1-azeemshaikh38@gmail.com
Signed-off-by: Azeem Shaikh 
Cc: Kees Cook 
Signed-off-by: Andrew Morton

audit: add space before parenthesis and around '=', "==", and '<'

2023-08-15T22:09:20+00:00

Fixes following checkpatch.pl issue:
ERROR: space required before the open parenthesis '('
ERROR: spaces required around that '='
ERROR: spaces required around that '<'
ERROR: spaces required around that '=='

Signed-off-by: Atul Kumar Pant 
[PM: subject line tweaks]
Signed-off-by: Paul Moore

acct: fix potential integer overflow in encode_comp_t()

2022-12-01T00:13:18+00:00

The integer overflow is descripted with following codes:
  > 317 static comp_t encode_comp_t(u64 value)
  > 318 {
  > 319         int exp, rnd;
    ......
  > 341         exp <<= MANTSIZE;
  > 342         exp += value;
  > 343         return exp;
  > 344 }

Currently comp_t is defined as type of '__u16', but the variable 'exp' is
type of 'int', so overflow would happen when variable 'exp' in line 343 is
greater than 65535.

Link: https://lkml.kernel.org/r/20210515140631.369106-3-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian 
Cc: Hanjun Guo 
Cc: Randy Dunlap 
Cc: Vlastimil Babka 
Cc: Zhang Jinhao 
Signed-off-by: Andrew Morton

acct: fix accuracy loss for input value of encode_comp_t()

2022-12-01T00:13:18+00:00

Patch series "Fix encode_comp_t()".

Type conversion in encode_comp_t() may look a bit problematic.


This patch (of 2):

See calculation of ac_{u,s}time in fill_ac():
  > ac->ac_utime = encode_comp_t(nsec_to_AHZ(pacct->ac_utime));
  > ac->ac_stime = encode_comp_t(nsec_to_AHZ(pacct->ac_stime));

Return value of nsec_to_AHZ() is always type of 'u64', but it is handled
as type of 'unsigned long' in encode_comp_t, and accuracy loss would
happen on 32-bit platform when 'unsigned long' value is 32-bit-width.

So 'u64' value of encode_comp_t() may look better.

Link: https://lkml.kernel.org/r/20210515140631.369106-1-zhengyejian1@huawei.com
Link: https://lkml.kernel.org/r/20210515140631.369106-2-zhengyejian1@huawei.com
Signed-off-by: Zheng Yejian 
Cc: Hanjun Guo 
Cc: Randy Dunlap  # build-tested
Cc: Vlastimil Babka 
Cc: Zhang Jinhao 
Signed-off-by: Andrew Morton

acct: use VMA iterator instead of linked list

2022-09-27T02:46:22+00:00

The VMA iterator is faster than the linked list.

Link: https://lkml.kernel.org/r/20220906194824.2110408-47-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Liam R. Howlett 
Acked-by: Vlastimil Babka 
Reviewed-by: Davidlohr Bueso 
Tested-by: Yu Zhao 
Cc: Catalin Marinas 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: SeongJae Park 
Cc: Sven Schnelle 
Cc: Will Deacon 
Signed-off-by: Andrew Morton